The flame-haired centre-half is likely to miss the derbies against Tottenham and Charlton - at the very least - next month when he has to return down under for international duty.
He says: "There are games in November, the friendly against France and two qualifiers after that.
"The two final games haven't been put in place, so I'm not sure exactly what dates they are.
"The France game is on November 11th; if I was away it would probably be three to four weeks depending on whether I am selected, the situation with West Ham, and what is happening with the international team.
"I have always said that playing for my country means a lot to me - I'm so proud to wear the green and gold.
"But it is difficult when this is your livelihood here; sometimes you go through a long spell when you don't play because you are injured or suspended, or the team is playing well, or you are not playing well.
"Then you do get back in the side and you have to go away again, then you return and are sitting around trying to get back in.
"I have always said I would always put my country first, but it is difficult because FIFA have set these dates smack bang in the middle of the season.
"The playoffs are going to be played in November for the European qualifiers so that is when we should play ours.
"That would cause a lot less problems, but the countries need the best squad available.
"When your country calls you back and you say 'no', the other players won't be happy, your country won't be happy, and the coaching staff won't be happy.
"I would never turn my back on Australia; it is a tough call - we will wait and see, and cross that bridge when it happens."
Hayden's disruption comes as he seeks to establish himself back in the side now he is free from injury.
"I have been back ten days and the finger is okay," he says.
"Originally they said they wanted me to rest for six weeks but I thought 'it's only a broken finger - no chance'.
"But with the screws in it the bone would have shattered if a ball had hit it."
He is pleased that the defence without him has looked fairly solid, though, and he says:
"It has been positive and negative; it is really good that the defence has been so tight.
"But you lose your spot and when people are playing well you have to wait to get back in there.
"But I will keep playing and when I get the chance I have got to try and keep my position.
"Of course I am a bit downhearted because I am a footballer and I want to play - that is what keeps you going.
"But that is the quality we have got in the squad at the moment; it is just unfortunate, but these things happen."
He insists that West Ham's position is a false one, and says:
"We have only played one game which was a bad game - at Middlesbrough.
"The luck hasn't gone our way; the first three games were encouraging and I'd say we deserved six or seven points.
"Hopefully the ball will bounce for us on Sunday, and we can eliminate the bad patches - but every team goes through one.
"If we get a couple of wins, we are right back up there.
"I don't think there is any need to panic - everyone is happy with what Glenn is doing, and he has got the team in a solid shape."
Hayden is delighted by the signing of Tomas Repka - even though he provides direct competition for him.
"He has got a great reputation and he looks a good, hard, mean defender," he says.
"It is the position I play so it is difficult, but all I can do is wait for my chance and hope to play well - if I that is what I do will keep my spot.
"He is more of a robust centre half and I am probably more of a playing centre half.
"The two might go together, the two might not; we won't know until we actually play together.
"I have enjoyed playing with Christian who helped me quite a lot, and had a good understanding with Ian Pearce.
"Given the chance I would love to play with Tomas."
Hayden is also pleased that the side are playing 4-4-2 under Glenn Roeder and adds:
"Everyone has their own different opinion, but in mine 4-4-2 is more compact and concrete."
Now he just wants to get on the field after a nightmare season last time around when a combination of bureaucracy and injury meant he hardly played for the Hammers.
"I'm just glad all that is behind me," he says, "I have got another three years left on my contract and I want to be part of it."