Google’s plan to launch an Android-based handset has reportedly been delayed. Although the Internet giant initially said Android handsets would be on the market sometime during the second half of this year, the company now says it expects to launch the first Android phone during Q4.

Citing people familiar with the situation, The Wall Street Journal reported that some Android partners, including carriers and application developers, are struggling to meet even the updated timeline. The report indicated that T-Mobile USA still hopes to be the first carrier to launch an Android handset before the end of this year, but that in working with T-Mobile Google has not had enough time or attention to work with Sprint Nextel, which had also hoped to launch an Android handset this year.

The Journal reported that China Mobile is suffering similar delays; it had hoped to launch an Android handset during Q3 but has reportedly delayed the launch until late this year or early 2009.

Handset makers also are reportedly experiencing delays integrating, testing and building carrier specific user interfaces on the open platform.

Google responded in the report, saying that the company is “very, very close” and that it is working with its hardware and software partners to help them develop new features and drive down the costs of implementing the new platform. Google already offers the open source platform to handset makers for free.

Google also said that it has received about 1,800 submissions to its mobile application development contest.