Clarke's worst round for more than two and a half years sent him on his way by lunchtime and then, after a five-hour wait, he was joined by Westwood, whose four-over-par total of 148 proved one too many.
While America's Gerry Norquist had his second successive 67 to put him on 10-under-par total and secure a five-stroke lead, Clarke's 79 meant he was near the rear of the 150-strong field on 11 over.
The last time the Ulsterman, second to Colin Montgomerie on last season's Order of Merit, scored higher than that was when he took 80 in the 1996 Scottish Open at Carnoustie.
Westwood, having also opened with a 76, had an eagle at the 520-yard 13th as he compiled a second-round 72, but it was not enough.
Clarke, who has not played since November, described his performance as "shockingly bad", adding "I came here with such high hopes, but there was nothing positive in that at all.
"Everything was unbelievably bad. I practised OK, but as soon as I teed up in the competition I was totally unable to hit it on the right side of the flag. The course is set up tough and I just kept hitting it in the rough."
Westwood, returning after an eight-week break, summed up his display with the words "very rusty" and "very scrappy".
The Ryder Cup pair were back on the Saujana course at breakfast time yesterday to complete first rounds held over because of lightning on Thursday.
Clarke's first shot was an eight-foot birdie attempt on the 14th, but he knocked it five feet past and missed the return. It set the tone for the day.
Setting off on his second round after a short break, he had a double- bogey at the second after a wild drive into a ditch and came home in a dreadful 42 with four bogeys and another double to finish.
Westwood had four holes of his first round to play on the resumption and finished them by taking three putts on the 18th for a bogey six.
When he did the same on the short 12th - his third of the second round - he knew he needed to improve if he was to survive.
On the very next hole the world No 6, winner of the event in 1997 and loser in a play-off last year, cut a superb five-wood over some trees on to the green at the 13th and holed from 20 feet for his eagle.
Twelve successive pars then followed before a bogey on the 413-yard eighth and a closing par left him dependent on others.
"It's about what I expected after eight weeks off," he said. "From walking 30 miles a week I've not been walking at all and you're bound to lose some strength."
Norquist, winner of the title in 1993 and second on the Asian money list three years ago, is five clear of a group of four: the Rochdale-born defending champion, Ed Fryatt, who has lived most of his life in Las Vegas, the Spaniard Tomas Munoz, the South Korean Choi Kyoung-ju and another American, Dean Wilson.
Greg Norman missed the cut for the first time in 22 years on Australian home soil yesterday, in the tournament bearing his name. The former world No 1 crashed out of the Greg Norman International at The Lakes, Sydney, an event he won last year, after adding a second round 76 to the 77 he shot on Thursday.Reuse content