Queensland police have defended the time it took to charge an officer with murdering his baby son, saying expert evidence in the case had taken months to obtain and verify.

The 38-year-old senior constable was charged with murder yesterday morning, 18 months after his two-month-old son succumbed to "fairly significant injuries" at Victoria Point in Brisbane's east.

According to The Sunday Mail , police will allege the Senior Constable was involved in a relationship with a woman who also worked for the Queensland Police Service.

His wife was reportedly not home when he called triple zero saying the baby had stopped breathing. He reportedly gave the two-month-old CPR with instructions from the operator.

Deputy Commissioner Steve Gollschewski said the baby's death was immediately considered suspicious and the officer was suspended "about a month after the incident".

Mr Gollschewski also defended the decision not to release any information about the incident before Saturday, including the fact an officer was suspended on suspicion of a child's murder, because detectives needed to maintain "the integrity of the investigation".

The deputy commissioner said police would allege the baby had suffered “fairly significant injuries”.

“I’m a father, these sorts of crimes - regardless of who commits them - are tragic and terrible,” Mr Gollschewski said.

“These sorts of investigations are very difficult and challenging and in this instance, protracted.”

The accused officer was suspended from duty about a month after the alleged incident “for the integrity of the investigation”, Mr Gollschewski said.

He said the officer had been on suspension on full pay but this would be reviewed now that charges had been laid.

Queensland Police Service pays its senior constables between $68,894 and $82,638 a year.