A Queensland mayor reportedly under investigation by the corruption watchdog says health issues have forced him to step down.

Ipswich Mayor Paul Pisasale held a press conference at St Andrew's Ipswich Private Hospital this week, saying issues to do with his multiple sclerosis had forced him to resign.

“Sometimes you think you're bulletproof ... when multiple sclerosis starts affecting your judgement and your ability to do your job 100 per cent its time to look after it,” he said.

“After 25 years and not having a weekend off and not having a holiday and getting so engrossed in the city it does take its toll.

“Now it's my time to look after my health.”

Deputy Mayor Paul Tully will be acting mayor until a by-election is held in three months’ time.

There are reports of an investigation into Mr Pisasale involving the Crime and Corruption Commission (CCC), and that police conducted a search of his office on Monday.

It came after Mr Pisasale was detained at Melbourne Airport last month with $50,000 in cash.

But the former Ipswich Mayor says he does not know of any looming matter.

“Over the years I've co-operated wholeheartedly with the CCC and I intend to continue to do that,” he said.