Kiama MP Gareth Ward, 44, is on trial in the NSW District Court after pleading not guilty to sexual intercourse without consent and indecent assault charges.
He is accused of inviting a drunk 18-year-old man to his South Coast home in February 2013 and indecently assaulting him three times in one night, despite his attempts to resist.
Two years later, the long-time MP allegedly sexually assaulted an intoxicated political staffer after a 2015 event at NSW Parliament House.
The man, aged 24 at the time, said Ward climbed into bed with him, groped his backside and sexually assaulted him despite him repeatedly saying "no".
During his testimony, the complainant was unable to definitively pinpoint the date of the alleged sexual assault but was "fairly certain" it happened in September.
In his first complaint to police, Ward's barrister David Campbell SC noted the man estimated it occurred between June and August 2015.
The complainant initially said Ward had assaulted him after a welcome drinks at Parliament House during that time, but later claimed it had been after an address by a senior politician.
"There is this pervading, inherent unreliability in the recall of (the complainant) as to when this occurred," Mr Campbell said during his closing remarks on Monday.
There is also "a very real question" as to whether the alleged offence occurred at Ward's apartment in Potts Point because cell tower records indicated the complainant was in the proximity of Parliament House at the relevant time, he argued.
But the crown prosecutor previously submitted the cell tower records are not conclusive proof of where someone was at a given time.
Ward's housemate told the jury he had been home on the night of the alleged assault and didn't see the complainant.
"Powerful evidence, we respectfully submit, as to where (the man) wasn't rather than where he was," Mr Campbell said.
Ward's housemate had not been questioned by the officer in charge, who Mr Campbell accused of "malevolence" and selectively cherry-picking what he wished to investigate.
The corrosive effect of time on memory meant uncertainty was rife throughout the complainant's report, Ward's lawyer contended.
He claimed the man had exaggerated after disclosing the alleged assault to a friend by telling her he had emailed then-NSW premier Gladys Berejiklian's office.
The friend then contacted police about the allegations, which Ward's lawyer suggested may have left the complainant stuck between a rock and a hard place.
"Could it be the case that (he) has been put into a position where, having brought forward to his friend a story that was not correct, he was caught and had to go on with it?" he asked.
"He couldn't say 'well look, nothing happened' because he was at a point of no return due to (his friend's) actions."
The crown prosecutor failed to prove their case beyond a reasonable doubt for either of the two complainants, Mr Campbell concluded, telling the jury Ward should be found not guilty on all counts.
The jury is expected to retire to consider verdicts on Tuesday.
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National Sexual Abuse and Redress Support Service 1800 211 028