A wave of climbers were heading for the summit of Mount Everest today in what is expected to be another busy weekend on the world's highest mountain.

Last weekend, four climbers died on their way down from the summit amid a "traffic jam" of more than 200 people scrambling to reach the top as the weather worsened.

A similar crowd is expected this weekend, but there have been no reports of climbers in trouble and the weather is good.

Gyanendra Shrestha, from Nepal's tourism ministry, said he had reports that 82 climbers reached the 29,035-foot summit this morning.

Shrestha, who is at the base camp, said 120 climbers started the last phase of the climb last night but not all of them reached the summit. He said it was normal for some of the climbers to quit at the last treacherous part of the climb for various reasons.

More climbers are expected to try to reach the summit tomorrow - probably the last day of this climbing season.

Another official, Mohan Krishna Sapkota, said: "This is the last chance for climbers to attempt to reach the summit. If they can't, then there is not going to be another opportunity this season."

The climbing season normally runs from late March to the first week in June, but this year the season's first clear conditions were last weekend.

Several climbers began their trek from the last camp at the South Col, located at 26,240 feet, last night and they climbed all night, reaching the summit this morning.

The deaths last weekend raised concerns about overcrowding above the highest trail on the mountain. The area above the South Col is nicknamed the "death zone" because of the steep, icy slope, treacherous conditions and low oxygen level.

Officials said climbers were heading to the summit last weekend as late as 2.30pm, even though 11am is the latest start time recommended.

That meant climbers were staying too long at high altitudes and exhausting their oxygen supplies because they did not anticipate having to wait.

More than 3,000 people have climbed Everest since Edmund Hillary and Tenzing Norgay became the first to do so in 1953. Some 225 climbers have died attempting it.

The deadliest day was May 10 1996, when eight people were killed. The main reason was said to be that climbers who started their ascent late in the day were caught in a snowstorm in the afternoon and lost their way.