Alleged killer asked sons for DNA test

A Melbourne man asked his two sons to take a DNA test because he didn't trust his ex-wife whom he is accused of murdering, a jury has heard.

Luke Paulino, 24, is giving evidence in the trial of his father, Fernando Paulino, who has pleaded not guilty to murdering his former wife, Teresa Paulino, 49 in 2013.

Luke Paulino said his father asked him and his older brother to take a DNA mouth swab test, shortly after accusing their mum of being in a pornography video.

"He said, 'I want you to do this to see if you guys are my boys, I don't trust your mum," Luke said.

He said his brother refused but he eventually agreed after his father persisted.

He said that afterwards, he never heard about the test again.

Luke told the jury his father had become increasingly angry after his mum began family court proceedings after their 2010 split, worried he would lose out on their assets.

He said his father threatened that she would "cop it" and didn't care if he went to jail. "I just want to make her suffer," he allegedly said.

The trial continues.