The jury considering its verdicts in the case of two men accused of murdering an undercover police officer in south Auckland in 2008 has been sent home for the night.

John Skinner, 38, and Iain Clegg, 36, have denied murdering Sergeant Don Wilkinson and attempting to murder another police officer, who has name suppression.

It is alleged the pair chased the officers after they tried to plant a tracking device on suspected drug dealer Skinner's car at his Mangere house on September 11, 2008.

The prosecution said that Skinner shot dead Mr Wilkinson with an airgun and seriously injured the second officer.

Skinner has admitted the killing but claimed he believed the two men were intruders and he feared for his life.

The jury of four women and eight men in the High Court at Auckland retired to consider its verdicts at 1.30pm today and was sent home at 5pm.

Justice Geoffrey Venning told the jury members they should ignore the extensive publicity about the case and put aside feelings of sympathy, when he summed up this morning.

He said police suspected Skinner of being involved with the manufacture of methamphetamine.

"You may have strong feelings about drugs, and as a result some of you may feel a degree of prejudice. Skinner is not here on drugs charges. He's on trial for murder and attempted murder," Justice Venning said.

There was no evidence to link Clegg in any way to the manufacture of methamphetamine, he told the jury.

If Mr Wilkinson had been wearing a protective vest he may not have been killed, Justice Venning added.

"You should not be distracted by the way police chose to carry out their operation that night. You are not here to conduct an inquiry into the police operation to determine what could have been done differently, you're here to assess the guilt of the accused," he told the jury.

He said it was up to the jury to decide on the credibility and reliability of witnesses.

The jury will continue its deliberations tomorrow morning.