A week after a sapping road trip to Adelaide in the heat, the Jets could barely deliver a punch in their 4-0 no-show at home on Sunday.

The contest was also played in stifling humidity at Newcastle International Sports Centre, but Merrick was in no mood for excuses post-game.

"I think I could find lots of excuses for them, but there shouldn't be any. That was just an extremely poor performance," Merrick said.

Merrick lashed out at a lack of urgency in defence and a wastefulness with the ball in the first half before showing marginal improvement in the second.

"To their credit it's only the second time they've done it. The last time was Sydney (FC). Other than that we've been very competitive," he said.

"We had a couple of decent shots but never really looked like scoring. Too many long balls from the back. Very unlike our team to play that style of football."

The display, coupled with the prospect of a challenging away game in Perth next week, prompted the veteran manager to suggest changes are likely to be made.

However, none are likely to come outside of Sunday's match-day squad, with injured imports Wes Hoolahan and Carlos Arroyo still over a month away.

Experienced defender Nigel Boogaard is an outside chance of a return.

"It was a bad day in the office," Merrick said.

"But I've got to have a good think about the next game against Perth Glory on Saturday, and freshen up the team because we can't turn out like that again.

"We've got some other boys on the bench we'll have a look at. I don't want to pick any of them out and say they did well when they went on (against City).

"I just think allround it was a very poor performance by Newcastle Jets and everyone has to take the blame for that, including myself."

Australian Associated Press